Fatigue behavior of Al18B4O33 whisker-framework reinforced Al matrix composites at high temperatures

The aluminum borate porous ceramic with whisker-framework structure was in situ synthesized and used to manufacture aluminum matrix composites by squeeze casting. The processing technique for the reinforcement was not only non-harmful to the environment and humans, but also relatively cost-effective compared to SiC whiskers. The microstructures were observed and analyzed. The aluminum borate whiskers are uniformly distributed and randomly oriented. Fatigue behavior of the composites was investigated at temperatures from room temperature to 723 K. Fatigue life increased with an increase in volume fraction of aluminum borates. The fatigue life was correlated with stress and temperature. The damage mechanisms of fatigue are cracking of primary Si and the whiskers at room temperature and cavitation in the matrix at high temperatures. (C) 2002 Elsevier Science Ltd. All rights reserved.